| Answer / Solution
A Preferred Roaming List (PRL) is a small data file stored inside of a CDMA modem which provides a list of alternate networks to use when the service provider's primary network cannot be reached (roaming). This allows the modem to choose the best roaming carriers, particularly "roaming partners" that the home carrier has a roaming agreement with, rather than using non-affiliated carriers which may incur additional roaming charges.
Each LAN-Cell CDMA model ships with the selected carrier's latest PRL file already loaded. In general, if your LAN-Cell is working properly and it is in a permanent stationary location, it is not necessary to update the PRL. However for mobile applications, you may need to periodically update the PRL file in the modem in order to obtain a signal in areas where coverage has been added either by your primary service provider or one of their partners.
The process for updating the PRL depends upon the CDMA carrier.
For Verizon Wireless USA, the LAN-Cell can automatically download and update its PRL over the air. To activate this process:
- Connect a terminal program (such as HyperTerm) to the LAN-Cell's CFG port.
- Slide the CFG switch to the left (CFG mode).
- Enter the command: AT+GMR
this will display the current PRL version.
- Enter the command: AT+CDV*22899
after a few seconds the LAN-Cell will request the PRL update from the network.
- Once you see the result: PROGRAMMING SUCCESSFUL!, wait 15 seconds then issue the AT+GMR command again to see the new PRL version.
- Return the CFG switch to the RUN (right) position and the LAN-Cell will reconnect to the cellular network.
Updating the PRL must be done via the CFG port and cannot be initiated remotely. The procedure for other CDMA carriers varies and may require external support software tools available from Proxicast. Contact Proxicast Technical support for more information on your specific carrier. Not all CDMA carriers use PRL files. GSM/GPRS devices do not use PRL files.
For LAN-Cell 2 models with PC-Card based modems, please refer to the instructions from your card manufacturer or cellular carrier for updating the PRL and/or firmware on the PC-Card using a Windows PC.